1. Field of the Invention
The present invention relates to a reaction block assembly capable of accommodating round bottom flasks, of different sizes, and is for use upon a magnetic stirrer integrated with a hot plate. Such stirrers generate a magnetic field, and various sizes of round bottom flasks are easily accommodated by this device for effective rotating the magnetic stir bars in the flask. The base of the assembly is aluminum and is configured to provide excellent heat transfer land and not to interfere with the magnetic field, being generated from below the hot plate surface.
2. Brief Description of the Prior Art
In the field of organic chemistry it is often desirable to perform a chemical reaction under precise heat transfer and stirring conditions. conditions. Known laboratory stirrers suited for use with the present invention include the Opti CHEM Model CG-1993-01 hot plate stirrer from Chemglass of Vineland NJ; the Ikamag RET, RCT and RH Basic magnetic stirrers from IKA of Germany; and the Heidolph MR3000 series of magnetic stirrers. Typically such hotplates are round and have a diameter of 135 mm, although some hotplate stirrers, such as the Snijders Model 34532, from Snijders of the Netherlands, employ a top plate diameter of 194 mm.
Magnetic stirrers that do not allow for heating are also known. Wanninger at al. (U.S. Pat. No. 5,547,280) illustrates a stirrer with a round, flat glass top. Other magnetic stirrers without a hotplate employ a 6 inch by 6 inch square top plate, such as the Model 1266 from Labline, or a square 7 inch by 7 inch square top plate, such as the Model S46720, from Thermolyne.
The use of reaction blocks to hold reaction vessels upon a surface of a magnetic stirrer is known. Landsburger (U.S. Pat. No. 3,356,316) illustrates a vinyl block with a plurality of test tube holders.
Where both stirring and heating are desired, prior art heat conduction blocks have been constructed of various configurations and materials. Kindmann (U.S. Pat. No. 5,529,391) illustrates thermoelectric elements and metal cooling fins attached to each of four sides of a square, aluminum heat conducting block, that then is positioned over a plurality of individual magnetic stirring devices. Ladlow et al. (U.S. Pat. No. 6,905,656) illustrates a solid adapter block with a plurality sockets to arrange test tubes outside of the periphery of a round hot plate stirrer, wherein the adapter block is said to be made of any chemically resistant material, such as PTFE, aluminum or stainless steel. Asynt, of the United Kingdom, sells a DrySyn aluminum adapter block for supporting a standard 1000 ml flask upon a round hot plate stirrer, with separate inserts available for accommodating 500 ml, 250 ml, 100 ml and 50 ml flasks, wherein two plastic handles are attached to opposing sides of a large aluminum block to allow lifting.
Such apparatus can overheat a hot plate, due to a large mass of aluminum, are difficult to manipulate and include large exposed surfaces that invite burns from inadvertent contact. The present device is advantageous over such known devices in that it allows a conventional magnetic stirrer to be used with various sizes of common round bottom flasks and features a flask holder with thin walls and a small aluminum mass, except about the center where the excellent heat transfer is concentrated. A heat shield is cooled by natural convection through interconnected narrow air spaces, and is easy and safe to manipulate, even when quickly taking the reaction block off the hot plate.